The present invention relates to a windshield wiper drive having a swivelably mounted drive shaft, a drive rocker arm immovably attached thereto, a connecting lever which is connected to the drive rocker arm via a first joint, a support rocker arm which is connected to the connecting lever via a second joint and is mounted via blind joint, and a windshield wiper arm that is connected to the connecting lever.
A windshield wiper drive is described in European Patent No. 0 182 123. It is used to move a windshield wiper blade attached to a windshield wiper arm in a back-and-forth movement across a windshield to be cleaned. To keep distortion from arising in the mechanism, which includes a drive rocker arm, a connecting lever, and a support rocker arm and is based on a four-joint mechanism, a fifth joint that divides the connecting lever into two sections that can be moved relative to one another is provided. The disadvantage of this is that it is relatively expensive to produce. Furthermore, using a fifth joint on the connecting lever is disadvantageous in terms of visual attractiveness.
An object of the present invention is to further refine a windshield wiper drive of the type described above so that it has a simpler design and is visually more attractive.
The windshield wiper drive has the advantage that either there is no need at all for the fifth joint, which means the design is simplified, or the fifth joint at least does not have to be arranged on the connecting lever but rather can be arranged on the drive rocker arm or the support rocker arm. Thus it is in a visually less obtrusive area when the windshield wiper drive is viewed.
According to a preferred embodiment of the present invention, the drive rocker arm has a swivel joint whose axis of rotation is roughly perpendicular to the axis of rotation of the drive rocker arm, the joint between the drive rocker arm and the connecting lever is a ball joint, and the joint between the connecting lever and the support rocker arm is a swivel joint. Alternatively, the support rocker arm has a swivel joint whose axis of rotation is roughly perpendicular to the axis of rotation of the support rocker arm, the joint between the support rocker arm and the connecting lever is a ball joint, and the joint between the connecting lever and the drive rocker arm is a swivel joint. In the case of these embodiments, a five-joint mechanism can be produced inexpensively, the fifth joint resulting in design and style advantages, e.g., a flatter design, thanks to the fact that it is arranged on a less exposed component, namely one of the rocker arms, and not on the connecting lever, which is the case in the prior art. Furthermore, this reliably keeps tolerances in the axial direction from leading to loss of smoothness of operation and increased wear and tear on the windshield wiper drive. Furthermore, it is possible to orient the axis of rotation of the drive rocker arm and the axis of rotation of the support rocker arm so that they are not parallel to one another.
According to another preferred embodiment, the joint is a ball joint, the joint between the support rocker arm and the connecting lever is a ball joint, and the joint between the connecting lever and the drive rocker arms is a swivel joint. In this embodiment, the four-joint mechanism has an additional degree of freedom thanks to the fact that two ball joints are used, so that tolerance compensation and offsetting of the axis of rotation of the drive rocker arm with respect to the axis of rotation of the support rocker arm relative to one another can be achieved without any difficulty. Furthermore, the design is particularly simple, and no expensive joint is required. Cost advantages can be achieved thanks to the simple design and the ease of assembly. Because there is no fifth joint, the design can be particularly flat, which ensures an attractive appearance.